[FFmpeg-user] Poor quality output when converting avi to mp4

[Ute Willmore]

Gyan,

I am still very new to video conversion and ffmpeg, so I don't understand
parts of your reply. Please explain:

What is non-standard about my input video?

I ran many conversion commands, and listed several of them in my original
message. Which one did you use?

What does "Muxing to TS" mean and why/how did you do that? What does
"Invalid NAL warnings mean?

I gather mp4box is another tool to use when dealing with videos and there
are all kinds of version available.

Is this the one you are using?
https://www.videohelp.com/software/MP4Box

I think you are saying that no matter what I will have to use MP4Box or
something similar to make a "standard" avi video and then convert that new
video to mp4 using the ffmpeg command you used. Is that correct?

Obviously, I would prefer not to process the video twice, because the real
video can be quite large. Do you have any idea what needs to be done to
produce a standard avi video in the first place?

Thanks

urw

On Mon, Jul 24, 2017 at 12:55 PM, Gyan <gyandoshi at gmail.com> wrote:

> On Mon, Jul 24, 2017 at 11:56 PM, Ute Willmore <uwillmore at remotegeo.com>
> wrote:
>
> > Hi everyone,
> >
> > I am hoping someone on this list can help me with a problem I am having
> > when converting a .avi video to .mp4 using FFmpeg. The output I get
> starts
> > out looking good, but then degrades and by the time the 18 second video
> > finishes it is hard to recognize what's on the screen. The colors are all
> > off, some areas are just single color blobs where there used to be trees.
> >
>
> Running your conversion command on your source, I see
>
> Input stream #0:0 (video): 856 packets read (18695093 bytes); 104 frames
> decoded;
>
> Muxing to TS and playing that throws invalid NAL warnings.
>
> So I ran
>
> mp4box -aviraw video hd.avi
>
> which produced hd_video.h264. This plays fine with ffplay.
>
> Running
>
> ffmpeg  -v verbose -i hd_video.h264 -i hd.avi -map 0 -map 1:a -vf
> scale=640:480 out.mp4
>
> produces an undistorted output.
>
> As best as I can tell, ffmpeg does have issues with parsing non-standard
> H.264 bitstreams. It's certainly not as resilient as other decoders.
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".